Stereoselective effect on ternary complexation of copper ions with N,N′-dimethyltartramide and mandelic acid

1983 ◽  
Vol 61 (9) ◽  
pp. 2151-2153
Author(s):  
Michelle M. Petit-Ramel ◽  
Gaël De Rycke ◽  
André Rio ◽  
Pierre E. Blond
Keyword(s):  
Aqueous Solution ◽  
Concentration Distribution ◽  
Mandelic Acid ◽  
Copper Ions ◽  
Mapping Method ◽  
Ternary Complexes ◽  
Ph Gradient ◽  
Potentiometric Measurements ◽  
Ternary Complexation ◽  
Ph Range

The binary and ternary complexation in aqueous solution between copper(II) ion,N,N′-dimethyltartramide (H2A) and mandelic acid (HB), were studied by potentiometric measurements in the 5–10 pH range at 25 °C and μ = 1 M in NaClO4. The titrations were analyzed using a pit-mapping method and the concentration distribution of the various simple and mixed complexes were plotted versus a pH gradient. A significant stereoselective effect is displayed in the ternary complexes only.

Complexes des ions Hg2+ avec Le monomère et le dimère de la thymine: 5-methyl-2,4 (1H, 3H) pyrimidinedione

1984 ◽  
Vol 62 (1) ◽  
pp. 22-26 ◽  
Author(s):  
M. M. Petit-Ramel ◽  
G. Thomas-David ◽  
G. Perichet ◽  
P. Pouyet
Keyword(s):  
Experimental Data ◽  
Concentration Distribution ◽  
Mapping Method ◽  
Association Constants ◽  
Chelate Complexes ◽  
Ph Titration ◽  
Complex Species ◽  
Wide Ph Range ◽  
Linear Configuration ◽  
Ph Range

The association constants for Hg2+-complexes involving monomeric (TM) and dimeric (TD) forms of thymine are determined by pH-titration measurements made over a wide pH range 2 < pH < 11. In both systems, the experimental data have been analyzed by a pit-mapping method and the concentration distribution of the various complex species is plotted versus a pH gradient.Because of the tendency of Hg2+ to form two bonds in a linear configuration, non-chelate complexes [Hg(TM)+] (log β101 = 10.65) and [Hg(TM)2] (log β102 = 20.70) are formed with the monomer thymine.Photodimers, obtained after irradiation of monomer thymine at 260 nm in frozen water (−10 °C), are the (meso)-cis, syn forms and can be complexed by the Hg2+ ions in [Hg(TD)] (log β101 = 13.55), [HgH−1 (TD)]− (log β1−11 = 6.73), and [HgH−2 (TD)]2− (log β1−21 = 1.69) species. [Hg(TD)] complex shows an absorption spectrum shifting towards 280 nm, whereas the free dimer ligand absorbs lower than 240 nm only. An irradiation at 280 nm provides the formation of the [Hg (TM)2] complex and consequently the breaking of the cyclobutane cycle in the dimer molecule.

scholarly journals Gallium (III)-acetate speciation studies under physiological conditions.

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Brahim HACHT
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
Experimental Investigation ◽  
Glass Electrode ◽  
Mononuclear Complex ◽  
Low Molecular Weight ◽  
Hydrogen Ions ◽  
Physiological Conditions ◽  
Potentiometric Measurements ◽  
Ph Range

This paper describes an experimental investigation in aqueous solution of the equilibria between gallium (III) metal ions and acetate ions as a model of low-molecular-weight ligand using potentiometric techniques under physiological conditions of temperature 37 °C and ionic strength 0.15 mol.dm-3 NaCl. Potentiometric measurements were monitored with the help of a glass electrode calibrated daily in hydrogen ions concentrations. Several metal to ligand ratios were used and the respective titrations data obtained in the pH range of 2.3-5.3 were treated using the SUPERQUAD computer program to determine global stability constants. Different species were considered during the calculation procedure and the following hydroxides have been characterized: ,  and coexist with one mononuclear complex Ga(CH3COO)+2. Speciation calculations based on the determined constants were then used to simulate the species distribution as a function of pH.

Schiff base equilibria. II. Beryllium complexes of N-n-butylsalicylideneimine and the hydrolysis of the Be2+ ion

1965 ◽  
Vol 18 (5) ◽  
pp. 651 ◽  
Author(s):  
RW Green ◽  
PW Alexander
Keyword(s):  
Aqueous Solution ◽  
Schiff Base ◽  
Complex Formation ◽  
Distribution Coefficient ◽  
Dilute Aqueous Solution ◽  
The Stability ◽  
Ph Range ◽  
Hydrolysis Of ◽  
Beryllium Complexes ◽  
Equilibria In Aqueous Solution

The Schiff base, N-n-butylsalicylideneimine, extracts more than 99.8% beryllium into toluene from dilute aqueous solution. The distribution of beryllium has been studied in the pH range 5-13 and is discussed in terms of the several complex equilibria in aqueous solution. The stability constants of the complexes formed between beryllium and the Schiff base are log β1 11.1 and log β2 20.4, and the distribution coefficient of the bis complex is 550. Over most of the pH range, hydrolysis of the Be2+ ion competes with complex formation and provides a means of measuring the hydrolysis constants. They are for the reactions: Be(H2O)42+ ↔ 2H+ + Be(H2O)2(OH)2, log*β2 - 13.65; Be(H2O)42+ ↔ 3H+ + Be(H2O)(OH)3-, log*β3 -24.11.

Effects of Aging on the Solubility of Palladium

1995 ◽  
Vol 412 ◽  
Author(s):  
C. Oda ◽  
H. Yoshikawa ◽  
M. Yui
Keyword(s):  
Aqueous Solution ◽  
Aging Time ◽  
Room Temperature ◽  
High Level Waste ◽  
Anaerobic Conditions ◽  
Dilute Aqueous Solution ◽  
Waste Repository ◽  
Ph Range ◽  
Effects Of Aging ◽  
High Level

AbstractPalladium solubility was measured in a dilute aqueous solution at room temperature in the pH range from 3 to 13 under anaerobic conditions. Crystalline Pd metal was clearly visible and the concentration of palladium in solution decreased gradually with aging time. The palladium concentrations in solution were less than 9.4×10-10M in the pH range from 4 to 10 and increased to 10-7M in the pH range greater than 10. This study suggests that palladium concentrations in certain high-level waste repository environments may be limited by Pd metal and may be less than 10-9M.

Micellar catalysis of organic reactions. VIII. Kinetic studies of the hydrolysis of 2-acetyloxybenzoic acid (aspirin) in the presence of micelles

1982 ◽  
Vol 35 (7) ◽  
pp. 1357 ◽  
Author(s):  
TJ Broxton
Keyword(s):  
Aqueous Solution ◽  
Cetyltrimethylammonium Bromide ◽  
Cetylpyridinium Chloride ◽  
Kinetic Studies ◽  
Base Catalysis ◽  
Plateau Region ◽  
General Base ◽  
Mechanism Of Hydrolysis ◽  
Ph Range ◽  
Hydrolysis Of

The hydrolysis of 2-acetyloxybenzoic acid in the pH range 6-12 has been studied in the presence of micelles of cetyltrimethylammonium bromide (ctab) and cetylpyridinium chloride (cpc). In the plateau region (pH 6-8) the hydrolysis is inhibited by the presence of micelles, while in the region where the normal BAC2 hydrolysis (pH > 9) occurs the reaction is catalysed by micelles of ctab and cpc. The mechanism of hydrolysis in the plateau region is shown to involve general base catalysis by the adjacent ionized carboxy group both in the presence and absence of micelles. This reaction is inhibited in the presence of micelles because the substrate molecules are solubilized into the micelle and water is less available in this environment than in normal aqueous solution.

scholarly journals An Investigation into the Adsorption of Aniline from Aqueous Solution Using H-Beta Zeolites and Copper-Exchanged Beta Zeolites

2005 ◽  
Vol 23 (3) ◽  
pp. 255-266 ◽  
Author(s):  
J. O'Brien ◽  
T. Curtin ◽  
T.F. O'Dwyer
Keyword(s):  
Aqueous Solution ◽  
Adsorption Process ◽  
Zeolite Beta ◽  
Langmuir Model ◽  
Beta Zeolite ◽  
Copper Leaching ◽  
Beta Zeolites ◽  
The Stability ◽  
Ph Range ◽  
Adsorbent Materials

Zeolite beta, a large-pore zeolite, was investigated in this study with a view to examining it as a potential adsorbent for the removal of aniline from aqueous solutions. Two different metal-loaded zeolites were prepared by exchanging H-beta zeolite (SiO2/Al2O3 = 75:1) with copper. The influence of exchanged copper on the uptake level was assessed. The effect of varying the silica-to-alumina ratio of the H-beta zeolite on the aniline uptake level was also examined, using three different H-beta zeolites with ratios of 25:1, 75:1 and 150:1 as adsorbents. The sorption experiments indicated an uptake level of ca. 110–120 mg/g for each zeolite and this level was also adsorbed by the copper-modified H-beta zeolites (SiO2/Al2O3 = 75:1). In all cases, the adsorption process followed the Langmuir model for adsorption and the level of aniline adsorbed was largely unaffected by a change in temperature or the presence of extra framework copper. The stability of the exchanged copper on these zeolites was then examined by measuring the quantity of copper leached from each zeolite into solution as a function of pH. Minimum copper leaching was observed in the pH range 5–11. This provided a stable pH working range for the adsorbent materials.

Study of colloidal properties of natural and Al-pillared smectite and removal of copper ions from an aqueous solution

2014 ◽  
Vol 36 (6) ◽  
pp. 786-795 ◽  
Author(s):  
Lucas Resmini Sartor ◽  
Antonio Carlos de Azevedo ◽  
Gabriel Ramatis Pugliese Andrade
Keyword(s):  
Aqueous Solution ◽  
Copper Ions ◽  
Colloidal Properties
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